CHAPTER 13. Spatial Maps and Ecosystem Models
IN THIS CHAPTER
- Introduction to spatial maps
- Isometric projections and ecosystem models
- Case Study: Gigamapping: Canadian Governance in the Digital Era
The cause of the great cholera outbreak in London in 1854 was initially unclear. Prior to Louis Pasteurâs germ theory, many thought the disease was in the air. John Snow, a London physician, had a different explanation. He believed cholera was in the water. After microscopic examinations were inconclusive, Snow instead analyzed the spread of cholera to prove his hunch.
To do this, Snow mapped cholera cases in Soho, London (Figure 13-1). The resulting patterns demonstrated causality: proximity to a certain water pump correlated to cholera cases with high predictability. The decline of cholera is credited to Snowâs recommendation to shut down that pump.
Snowâs map contains multiple layers of informationâstreets, houses with cholera cases, and water pumpsâjust enough to reveal previously undetected evidence (in this case, the cause of a disease). The approach is simple but effective: Snow was able to generate a hypothesis based on his simple map: if the city shuts down a specific pump, then cases ...